Energy storage device and energy storage device production method

ABSTRACT

An energy storage device includes an electrode body in which an electrode is stacked, a container in which the electrode body is accommodated, a cover plate structure including a cover plate that closes the container, and a spacer that is attached to the electrode body. The spacer includes a positioning unit that positions the cover plate structure. An engaging unit, engaging with the positioning unit, is provided in the cover plate structure.

The present application is a Divisional Application of U.S. patentapplication Ser. No. 15/760,929, filed on Mar. 16, 2018, which is basedon International Application No. PCT/JP2016/077542, filed on Sep. 16,2016, which is based on Japanese Patent Application No. 2015-186090,filed on Sep. 18, 2015, the entire contents of which are incorporatedherein by reference.

TECHNICAL FIELD

The present invention relates to an energy storage device and an energystorage device production method.

BACKGROUND ART

Conventionally, there is well known an energy storage device that isassembled by inserting electrode body in a container with a spacerattached to the electrode body (for example, see Patent Document 1).

PRIOR ART DOCUMENT Patent Document

Patent Document 1: JP-A-2011-216239

SUMMARY OF THE INVENTION Problems to be Solved by the Invention

When the electrode body is inserted in the container while the spacer isattached to the electrode body, it is necessary to press and push theelectrode body itself, and there is a risk of damaging an electrodeplate constituting the electrode body such that the electrode body iscrushed during the insertion.

An object of the present invention is to provide an energy storagedevice and a production method thereof, for being able to prevent thedamage of the electrode body during the production.

MEANS FOR SOLVING THE PROBLEMS

An energy storage device according to one aspect of the presentinvention includes: an electrode body including a curved portion that isformed by winding an electrode; a container in which the electrode bodyis accommodated; a cover plate structure including a cover plate thatcloses the container; and a spacer that is attached to the curvedportion of the electrode body, one end portion of the spacer abutting ona part of the cover plate structure. The electrode body is accommodatedin the container while one end portion in a winding axis direction ofthe electrode body faces the cover plate structure.

Advantages of the Invention

According to the present invention, the damage of the electrode body canbe prevented during the production.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view illustrating an appearance of an energystorage device according to an embodiment.

FIG. 2 is an exploded perspective view illustrating the energy storagedevice of the embodiment.

FIG. 3 is an exploded perspective view illustrating a cover platestructure of the embodiment.

FIG. 4 is a perspective view illustrating a configuration of anelectrode body of the embodiment.

FIG. 5 is a sectional view schematically illustrating an adhesion stateof an adhesive tape to a body portion of the electrode body of theembodiment.

FIG. 6 is a front view illustrating a side spacer of the embodiment whenthe side spacer is viewed from an inside.

FIG. 7 is a sectional view of the side spacer taken on an XY-planepassing through a line VII-VII in FIG. 6.

FIG. 8 is a plan view illustrating the side spacer of the embodiment.

FIG. 9 is a perspective view illustrating an assembly state of the sidespacer and the electrode body of the embodiment.

FIG. 10 is a side view illustrating a positional relationship between acover plate structure and the side spacer of the embodiment.

FIG. 11 is a sectional schematic diagram illustrating the cover platestructure of the embodiment and a surrounding structure thereof.

FIG. 12 is a perspective view illustrating a binding state of a bindingsheet to the electrode body of the embodiment.

FIG. 13 is a perspective view illustrating one process of an energystorage device production method of the embodiment.

FIG. 14 is a sectional view illustrating a positional relationship amongthe side spacer, the electrode body, and the container of theembodiment.

FIG. 15 is a perspective view illustrating a state in which a sidespacer according to a modification of the embodiment is attached to theelectrode body.

FIG. 16 is a perspective view illustrating a state in which a sidespacer according to another modification of the embodiment is attachedto the electrode body.

FIG. 17 is a sectional view illustrating a positional relationshipbetween a side spacer according to still another modification of theembodiment and the container.

MODE FOR CARRYING OUT THE INVENTION

An energy storage device according to one aspect of the presentinvention includes: an electrode body including a curved portion that isformed by winding an electrode; a container in which the electrode bodyis accommodated; a cover plate structure including a cover plate thatcloses the container; and a spacer that is attached to the curvedportion of the electrode body, one end portion of the spacer abutting ona part of the cover plate structure. The electrode body is accommodatedin the container while one end portion in a winding axis direction ofthe electrode body faces the cover plate structure.

In this configuration, because the cover plate structure abuts partiallyon one end portion of the spacer attached to the electrode body, theelectrode body enters the container together with the spacer when thecover plate structure is pressed in assembling the electrode body in thecontainer. Accordingly, even if the electrode body is not directlypressed, the electrode body can be accommodated in the container, andthe damage of the electrode body can be prevented during the production.

In the energy storage device, the spacer may extend from one end portionto the other end portion in the winding axis direction of the electrodebody.

In this configuration, the spacer extends from one end portion of theelectrode body to the other end portion, so that the spacer can be slidto the end with respect to the container when the electrode body isaccommodated in the container. Accordingly, the electrode body caneasily be guided into the container.

In the energy storage device, the spacer may include a bottom plate,which partially covers the other end portion of the electrode body, inthe other end portion in the winding axis direction.

In this configuration, the bottom plate partially covering the other endportion of the electrode body is provided in the other end portion ofthe spacer, so that the other end portion of the electrode body can beprevented from contacting partially with the container after theelectrode body is accommodated in the container. Therefore, the damageof the electrode body can further be prevented.

In the energy storage device, the spacer may include a top plate that isinterposed between one end portion and the container in the winding axisdirection of the electrode body to cover a part of one end portion ofthe electrode body.

In this configuration, the top plate partially covering one end portionof the electrode body is provided in the spacer, so that one end portionof the electrode body can be prevented from contacting with thecontainer after the electrode body is accommodated in the container.Therefore, the damage of the electrode body can further be prevented.

In the energy storage device, the spacer may include a positioning unitthat positions the cover plate structure, and an engaging unit engagingthe positioning unit may be provided in the cover plate structure.

In this configuration, the engaging unit of the cover plate structureengages the positioning unit of the spacer to position the cover platestructure with respect to the spacer. Accordingly, the electrode bodycan be accommodated in the container while the positional relationshipbetween the spacer and the cover plate structure is stabilized.

In the energy storage device, the cover plate structure may include aninsulating member that is disposed between the cover plate and theelectrode body, and the engaging unit may be provided in the insulatingmember.

In this configuration, the insulating member is provided between thecover plate and the electrode body, so that the insulating propertybetween the cover plate and the electrode body can be maintained by theinsulating member. The engaging unit is provided in the insulatingmember, so that the position of the insulating member can be stabilized.

In the energy storage device, one end portion of the spacer may separatefrom the electrode body in the winding axis direction.

In this configuration, because one end portion of the spacer separatesfrom the electrode body in the winding axis direction, the spacer doesnot interfere with one end portion of the electrode body even if thecover plate structure is pushed. Therefore, the damage of the electrodebody can further be prevented during the production.

In the energy storage device, the cover plate structure may include acurrent collector, and the electrode body may include a tab that iselectrically connected to the current collector.

In this configuration, even if the tab is provided in the electrodebody, the damage of the tab can be prevented because the electrode bodycan be accommodated in the container without directly pressing theelectrode body.

An energy storage device according to another aspect of the presentinvention includes: an electrode body in which an electrode is wound; acontainer in which the electrode body is accommodated; a cover platestructure including a cover plate that closes the container; and aspacer that is attached to the electrode body, one end portion of thespacer abutting on a part of the cover plate structure. The electrodebody is accommodated in the container while one end portion in a windingaxis direction of the electrode body faces the cover plate structure.

In this configuration, because the cover plate structure abuts partiallyon one end portion of the spacer attached to the electrode body, theelectrode body enters the container together with the spacer when thecover plate structure is pressed in assembling the electrode body in thecontainer. Accordingly, even if the electrode body is not directlypressed, the electrode body can be accommodated in the container, andthe damage of the electrode body can be prevented during the production.

A method according to still another aspect of the present invention isfor producing an energy storage device including a containeraccommodating an electrode body including a curved portion that isformed by winding an electrode; a cover plate structure including acover plate that closes the container; and a spacer that is attached tothe electrode body. At this point, the cover plate structure is pushedwhile one end portion on the cover plate structure side of the spacerattached to the electrode body abuts on a part of the cover platestructure, and the electrode body is accommodated in the container whileone end portion in a winding axis direction of the electrode body facesthe cover plate structure.

In this configuration, when the cover plate structure is pushed whileone end portion on the spacer abuts on a part of the cover platestructure, because the electrode body is accommodated in the container,the electrode body can be accommodated in the container without directlypressing the electrode body, and the damage of the electrode body can beprevented during the production.

Hereinafter, an energy storage device according to an exemplaryembodiment of the present invention will be described with reference tothe drawings. Each drawing is a schematic diagram, but not alwaysstrict.

The following embodiment illustrates one specific example of the presentinvention. A shape, a material, a component, disposition position andconnection form of the component, and a procedure of productionprocesses in the embodiment are illustrated only by way of example, butdo not restrict the present invention. In the components of theembodiment, the component that is not described in an independent claimindicating the highest concept is described as optional component.

An energy storage device 10 of the embodiment will generally bedescribed with reference to FIGS. 1 to 3.

FIG. 1 is a perspective view illustrating an appearance of the energystorage device 10 of the embodiment. FIG. 2 is an exploded perspectiveview illustrating the energy storage device 10 of the embodiment. FIG. 3is an exploded perspective view illustrating a cover plate structure 180of the embodiment. In FIG. 3, broken lines indicate a positive electrodeleading plate 145 and a negative electrode leading plate 155, and thepositive electrode leading plate 145 and the negative electrode leadingplate 155 are connected to a positive electrode current collector 140and a negative electrode current collector 150, which are included inthe cover plate structure 180.

In FIG. 1 and the drawings subsequent to FIG. 1, for convenience, thedescription is made while a Z-axis direction is set to a verticaldirection.

However, sometimes the Z-axis direction is not always matched with thevertical direction in an actual use mode.

The energy storage device 10 is a secondary battery that can charge anddischarge electricity. Specifically, the energy storage device 10 is anonaqueous electrolyte secondary battery such as a lithium ion secondarybattery. For example, the energy storage device 10 is applied to anelectric vehicle (EV), a hybrid electric vehicle (HEV), or a plug-inhybrid electric vehicle (PHEV). The energy storage device 10 is notlimited to the nonaqueous electrolyte secondary battery, but may be asecondary battery except for the nonaqueous electrolyte secondarybattery or a capacitor.

As illustrated in FIGS. 1 and 2, the energy storage device 10 includesan electrode body 400 and a container 100 that accommodates theelectrode body 400 therein. In the embodiment, the cover plate structure180 that is constructed by disposing various elements on the cover plate110 of the container 100 is disposed above the electrode body 400. Inthe container 100, one end portion of the electrode body 400 faces thecover plate structure 180.

The cover plate structure 180 includes a cover plate 110 of thecontainer 100, a positive electrode terminal 200, a negative electrodeterminal 300, upper insulating members 125 and 135, lower insulatingmembers 120 and 130, the positive electrode current collector 140, andthe negative electrode current collector 150.

The positive electrode terminal 200 is electrically connected to apositive electrode of the electrode body 400 through the positiveelectrode current collector 140, and the negative electrode terminal 300is electrically connected to a negative electrode of the electrode body400 through the negative electrode current collector 150. Each ofconductive members, such as the positive electrode terminal 200, whichare electrically connected to the electrode body 400, is insulated fromthe container 100 by insulating members such as the lower insulatingmember 120.

In each of the upper insulating members 125 and 135 and the lowerinsulating members 120 and 130, at least a part is the insulating memberdisposed between the wall portion of the container 100 and theconductive member. In the embodiment, each insulating member is disposedalong the cover plate 110 constituting an upper wall portion in six wallportions of the container 100 having a substantially rectangularparallelepiped external form.

In addition to the above configuration, the energy storage device 10 ofthe embodiment includes an upper spacer 500 and a cushion sheet 600,which are disposed between the cover plate structure 180 and theelectrode body 400.

The upper spacer 500 is disposed between the electrode body 400 and thecover plate 110, and includes a latch 510 that is partially latched inthe cover plate structure 180.

Specifically, the upper spacer 500 has a flat shape as a whole, andincludes two latches 510 and two insertion portions 520 in which thetabs 410 and 420 are inserted (the two insertion portions 520 that thetab 410 and 420 pierce). In the embodiment, the insertion portion 520 isprovided into a notch shape in the upper spacer 500. The upper spacer500 is made of a material, such as polycarbonate (PC), polypropylene(PP), polyethylene (PE), and polyphenylene sulfide resin (PPS), whichhas an insulating property.

For example, the upper spacer 500 acts as a member that directly orindirectly controls upward movement (direction to the cover plate 110)of the electrode body 400, or a member that prevents a short circuitbetween the cover plate structure 180 and the electrode body 400. Theupper spacer 500 includes the two latches 510, and each of the twolatches 510 is latched in an attaching unit 122 or 132 included in thecover plate structure 180.

The cushion sheet 600 is made of a highly flexible, porous material suchas foamed polyethylene, and acts as a cushion material between theelectrode body 400 and the upper spacer 500.

In the embodiment, a side spacer (spacer) 700 is disposed between a sidesurface (in the embodiment, both side surfaces in an X-axis direction)in a direction intersecting a direction (Z-axis direction) parallel tothe electrode body 400 and cover plate 110 and an inner peripheralsurface of the container 100 in the electrode body 400. For example, theside spacer 700 has a function of controlling a position of theelectrode body 400. A specific configuration of the side spacer 700 isdescribed later.

In addition to the components in FIGS. 1 to 3, the energy storage device10 may include another element, such as a cushion sheet disposed betweenthe electrode body 400 and a bottom 113 of the container 100 (main body111). Although an electrolyte solution (nonaqueous electrolyte) issealed in the container 100 of the energy storage device 10, theelectrolyte solution is not illustrated.

The container 100 includes the main body 111 and the cover plate 110.There is no particular limitation to a material for the main body 111and the cover plate 110. For example, the main body 111 and the coverplate 110 are made of weldable metal such as stainless steel, aluminum,and aluminum alloy.

The main body 111 is formed into a tubular body having a rectangularshape in a plan view. The main body 111 includes an accommodation recess112 having a rectangular shape in a plan view and a bottom 113. Aninsulating sheet 350 covering the electrode body 400 is provided in themain body 111.

The cover plate 110 is welded after the electrode body 400, theinsulating sheet 350, and the like are accommodated in the accommodationrecess 112, whereby the inside of the main body 111 is sealed.

The cover plate 110 is a plate-like member that closes the accommodationrecess 112. As illustrated in FIGS. 2 and 3, a safety valve 170, anelectrolyte solution filling port 117, through-holes 110 a and 110 b,and two swelling units 160 are formed in the cover plate 110. The safetyvalve 170 is opened when an inner pressure of the container 100increases, whereby the safety valve 170 has a function of releasing gasin the container 100.

The electrolyte solution filling port 117 is a through-hole throughwhich the electrolyte solution is poured in producing the energy storagedevice 10. As illustrated in FIGS. 1 to 3, an electrolyte solutionfilling plug 118 is disposed in the cover plate 110 in order to closethe electrolyte solution filling port 117. That is, in producing theenergy storage device 10, the electrolyte solution is poured into thecontainer 100 from the electrolyte solution filling port 117 into thecontainer 100, and the electrolyte solution filling plug 118 is weldedto the cover plate 110 to close the electrolyte solution filling port117, thereby accommodating the electrolyte solution in the container100.

Any solution can be selected as the electrolyte solution sealed in thecontainer 100 without restriction as long as the solution does notdamage performance of the energy storage device 10.

In the embodiment, each of the two swelling units 160 is provided in thecover plate 110 by forming a part of the cover plate 110 into a swellingshape. For example, the two swelling unit 160 is used to position theupper insulating member 125 or 135. A recess (not illustrated) that isconcave upward is formed on a rear side (the side opposite to theelectrode body 400) of the swelling unit 160, and an engagementprojection 120 b or 130 b of the lower insulating member 120 or 130engages a part of the recess. Therefore, the lower insulating member 120or 130 is positioned, and fixed to the cover plate 110 at this point.

The upper insulating member 125 electrically insulates the positiveelectrode terminal 200 from the cover plate 110. The lower insulatingmember 120 electrically insulates the positive electrode currentcollector 140 from the cover plate 110. The upper insulating member 135electrically insulates the negative electrode terminal 300 from thecover plate 110. The lower insulating member 130 electrically insulatesthe negative electrode current collector 150 from the cover plate 110.For example, sometimes the upper insulating members 125 and 135 arereferred to as an upper gasket, and the lower insulating members 120 and130 are referred to as a lower gasket. That is, in the embodiment, theupper insulating members 125 and 135 and the lower insulating members120 and 130 have a function of sealing gaps between the electrodeterminals (200 and 300) and the container 100.

Similarly to the upper spacer 500, the upper insulating members 125 and135 and the lower insulating members 120 and 130 are made of thematerial, such as PC, PP, PE, or PPS, which has the insulating property.In the lower insulating member 120, a through-hole 126 guiding theelectrolyte solution flowing from the electrolyte solution filling port117 toward the electrode body 400 is made in a portion locatedimmediately below the electrolyte solution filling port 117.

Engaging units 121 and 131 engaging the side spacer 700 are provided inthe lower insulating member 120 and 130, respectively. Specifically,each of the engaging units 121 and 131 projects from one end on anoutside of each of the lower insulating members 120 and 130. When theengaging units 121 and 131 engage the side spacer 700, the lowerinsulating members 120 and 130 are positioned with respect to the sidespacer 700. Therefore, the cover plate structure 180 is positioned withrespect to the side spacer 700. An engagement state between the engagingunits 121 and 131 and the side spacer 700 is described later.

As illustrated in FIGS. 1 to 3, the positive electrode terminal 200 iselectrically connected to the positive electrode of the electrode body400 through the positive electrode current collector 140. The negativeelectrode terminal 300 is electrically connected to the negativeelectrode of the electrode body 400 through the negative electrodecurrent collector 150. That is, the positive electrode terminal 200 andthe negative electrode terminal 300 are a metallic electrode terminalused to introduce electricity stored in the electrode body 400 to anouter space of the energy storage device 10, or to introduce theelectricity to an inner space of the energy storage device 10 in orderto store the electricity in the electrode body 400. The positiveelectrode terminal 200 and the negative electrode terminal 300 are madeof aluminum or aluminum alloy.

A fastening unit 210 is provided in the positive electrode terminal 200in order to fasten the container 100 and the positive electrode currentcollector 140 to each other. A fastening unit 310 is provided in thenegative electrode terminal 300 in order to fasten the container 100 andthe negative electrode current collector 150 to each other.

The fastening unit 210 is a member (rivet) extending downward from thepositive electrode terminal 200, and the fastening unit 210 is insertedand caulked in a through-hole 140 a of the positive electrode currentcollector 140. Specifically, the fastening unit 210 is inserted andcaulked in a through-hole 125 a of the upper insulating member 125, thethrough-hole 110 a of the cover plate 110, a through-hole 120 a of thelower insulating member 120, and a through-hole 140 a of the positiveelectrode current collector 140. Therefore, the positive electrodeterminal 200 and the positive electrode current collector 140 areelectrically connected to each other, and the positive electrode currentcollector 140 is fixed to the cover plate 110 together with the positiveelectrode terminal 200, the upper insulating member 125, and the lowerinsulating member 120.

The fastening unit 310 is a member (rivet) extending downward from thenegative electrode terminal 300, and the fastening unit 310 is insertedand caulked in the through-hole 150 a of the negative electrode currentcollector 150. Specifically, the fastening unit 310 is inserted andcaulked in a through-hole 135 a of the upper insulating member 135, thethrough-hole 110 b of the cover plate 110, the through-hole 130 a of thelower insulating member 130, and the through-hole 150 a of the negativeelectrode current collector 150. Therefore, the negative electrodeterminal 300 and the negative electrode current collector 150 areelectrically connected to each other, and the negative electrode currentcollector 150 is fixed to the cover plate 110 together with the negativeelectrode terminal 300, the upper insulating member 135, and the lowerinsulating member 130.

The fastening unit 210 may be formed integrally with the positiveelectrode terminal 200, or the fastening unit 210 that is preparedseparately from the positive electrode terminal 200 may be fixed to thepositive electrode terminal 200 by a technique such as caulking andwelding. The same holds true for a relationship between the fasteningunit 310 and the negative electrode terminal 300.

The positive electrode current collector 140 is disposed between theelectrode body 400 and the container 100 to electrically connect theelectrode body 400 and the positive electrode terminal 200. The positiveelectrode current collector 140 is made of aluminum or aluminum alloy.In the embodiment, the positive electrode current collector 140 iselectrically connected to the tab 410 on the positive electrode side ofthe electrode body 400 through the positive electrode leading plate 145of the leading plate. Similarly to the positive electrode currentcollector 140, the positive electrode leading plate 145 is made ofaluminum or aluminum alloy.

The negative electrode current collector 150 is disposed between theelectrode body 400 and the container 100 to electrically connect theelectrode body 400 and the negative electrode terminal 300. The negativeelectrode current collector 150 is made of copper or copper alloy. Inthe embodiment, the negative electrode current collector 150 iselectrically connected to the tab 420 on the negative electrode side ofthe electrode body 400 through the negative electrode leading plate 155of the leading plate. Similarly to the negative electrode currentcollector 150, the negative electrode leading plate 155 is made ofcopper or copper alloy.

A connection portion of the current collector and the tab with theleading plate interposed therebetween is described in detail later.

A configuration of the electrode body 400 will be described below withreference to FIG. 4.

FIG. 4 is a perspective view illustrating the configuration of theelectrode body 400 of the embodiment. In FIG. 4, a winding state of theelectrode body 400 is illustrated while partially developed.

The electrode body 400 is a power generation element in which theelectricity can be stored. The electrode body 400 is formed byalternately laminating and winding a positive electrodes 450 and anegative electrode 460 and separators 470 a and 470 b. That is, thepositive electrode 450, the separator 470 a, the negative electrode 460and the separator 470 b are laminated in this order, and wound such thatsections of the positive electrode 450, the separator 470 a, thenegative electrode 460 and the separator 470 b are formed into an ovalshape, thereby forming the electrode body 400.

The positive electrode 450 is an electrode plate in which a positiveactive material layer is formed on a surface of a positive electrodesubstrate layer of an elongated belt-like metallic foil made of aluminumor aluminum alloy. Any well-known material can properly be used as thepositive active material for the positive active material layer as longas the material can occlude and emit lithium ions. For example,polyanion compounds such as LiMPO₄, LiMSiO₄, and LiMBO₃ (M is one or atleast two kinds of transition metals selected from Fe, Ni, Mn, Co, andthe like), spinel compounds such as lithium titanate and lithiummanganate, and lithium transition metal oxides such as LiMO₂ (M is oneor at least two kinds of transition metals selected from Fe, Ni, Mn, Co,and the like) can be used as the positive active material.

The negative electrode 460 is an electrode plate in which a negativeactive material layer is formed on a surface of a negative electrodesubstrate layer of an elongated belt-like metallic foil made of copperor copper alloy. Any well-known material can properly be used as thenegative active material for the negative active material layer as longas the material can occlude and emit lithium ions. Example of thenegative active materials include lithium metal, lithium alloy (lithiummetal-containing alloys such as lithium-aluminum, lithium-lead,lithium-tin, lithium-aluminum-tin, lithium-gallium, and Wood's metal),alloys that can occlude and emit lithium, carbon materials (such asgraphite, non-graphitizing carbon, graphitizing carbon, low-temperaturesintered carbon, and amorphous carbon), metal oxides, lithium metaloxides (such as Li₄Ti₅O₁₂), and polyphosphoric acid compounds.

The separators 470 a and 470 b are microporous sheet made of resin. Anywell-known material can properly be used as the material for theseparators 470 a and 470 b used in the energy storage device 10 as longas the material does not degrade performance of the energy storagedevice 10.

The positive electrode 450 includes plural projections 411 that projectoutward at one end in a winding axis direction. Similarly, the negativeelectrode 460 includes plural projections 421 that project outward atone end in the winding axis direction. The plural projections 411 andthe plural projections 421 are a portion (active material uncoatedportion) in which the substrate layer is exposed while not coated withthe active material.

As used herein, the winding axis means a virtual axis that becomes acenter axis about which the positive electrode 450 and the negativeelectrode 460 are wound. In the embodiment, the winding axis is astraight line passing through the center of the electrode body 400 inparallel to the Z-axis direction.

The plural projections 411 and the plural projections 421 are disposedat the end (the end on the positive side of the Z-axis direction in FIG.4) on the identical side in the winding axis direction, and the positiveelectrode 450 and the negative electrode 460 are laminated, therebylaminating the plural projections 411 and the plural projections 421 atpredetermined positions of the electrode body 400. Specifically, thepositive electrode 450 is wound and laminated to laminate the pluralprojections 411 at the predetermined position in a circumferentialdirection at one end in the winding axis direction. The negativeelectrode 460 is wound and laminated to laminate the plural projections421 at the predetermined position different from the position where theplural projections 411 are laminated in the circumferential direction atone end in the winding axis direction.

Resultantly, the tab 410 formed by laminating the plural projections 411and the tab 420 formed by laminating the plural projections 421 areformed in the electrode body 400. For example, the tab 410 is collectedtoward the center in the laminating direction, and joined to thepositive electrode leading plate 145 by ultrasonic welding. For example,the tab 420 is collected toward the center in the laminating direction,and joined to the negative electrode leading plate 155 by ultrasonicwelding. The positive electrode leading plate 145 joined to the tab 410is joined to the positive electrode current collector 140, and thepositive electrode leading plate 145 joined to the tab 420 is joined tothe negative electrode current collector 150.

The tab (410 and 420) introduces and leads out the electricity in theelectrode body 400, and sometimes other names such as “lead” and a“current collector” are given to the tab.

The tab 410 does not contribute power generation because the tab 410 isformed by laminating the projection 411 of the portion in which thesubstrate layer is exposed. Similarly, the tab 420 does not contributethe power generation because the tab 420 is formed by laminating theprojection 421 of the portion in which the substrate layer is exposed.On the other hand, in the electrode body 400, a portion other than thetabs 410 and 420 contributes the power generation because the portion isformed by laminating the portion in which the active material is coatedwith the substrate layer. Hereinafter, the portion other than the tabs410 and 420 is referred to as a body portion 430. Both end portions inan X-axis direction of the body portion 430 constitute curved portions431 and 432 in which outer peripheral surfaces are bent. Thus, theelectrode body 400 is formed into an oval shape having the curvedportions 431 and 432.

In order to prevent a winding deviation, an adhesive tape 370 isattached to three points of each of one end portion and the other endportion in a winding axis direction (Z-axis direction) of the bodyportion 430 (see FIG. 9).

FIG. 5 is a sectional view schematically illustrating an adhesion stateof the adhesive tape 370 to the body portion 430 of the electrode body400.

FIG. 5 illustrates the states of one adhesive tape 370 adhering to alower end portion of the body portion 430 and the positive electrode450, negative electrode 460, and separators 470 a and 470 b, which aresandwiched between both end portions of the adhesive tape 370. The sameholds for the adhesion state in other adhesive tapes 370, and thedescription is omitted. In FIG. 5, for convenience, the positiveelectrode 450, the negative electrode 460, and the separators 470 a and470 b do not correspond to the actual winding numbers.

As illustrated in FIG. 5, the end portions of the separators 470 a and470 b stick out of the positive electrode 450 and the negative electrode460. The end portions of the adhesive tape 370 adhere to the outerperipheral surface of the body portion 430 so as to bring the stick-outportions 470 c and 470 d of the separators 470 a and 470 b close to thecenter. Therefore, even in the portion in which the adhesive tape 370does not exist, the stick-out portion 470 c and 470 d of the separator470 a and 470 b close the end portion of the body portion 430, and aforeign substance is prevented from mixing into the body portion 430while the winding deviation of the body portion 430 is suppressed.

A specific configuration of the side spacer 700 will be described below.

FIG. 6 is a front view illustrating the side spacer 700 of theembodiment when the side spacer 700 is viewed from an inside. FIG. 7 isa sectional view of the side spacer 700 taken on an XY-plane passingthrough a line VII-VII in FIG. 6. FIG. 8 is a plan view illustrating theside spacer 700 of the embodiment. In FIG. 6, the external form of thebody portion 430 of the electrode body 400 is indicated by an alternatelong and two short dashes line. FIG. 8 illustrates the state in whichthe engaging unit 131 of the lower insulating member 130 engages theside spacer 700. The same hold for the positive electrode side, and thedescription is omitted.

As illustrated in FIGS. 6 to 8, the side spacer 700 is an elongatedmember extending in the winding axis direction (Z-axis direction), andis constructed with a material, such as PC, PP, PE, or PPS, which has aninsulating property. The side spacer 700 includes a base 710, a wall720, and a bottom plate 730.

The base 710 includes a top plate 711 and a wall portion 712.

When viewed from above, the top plate 711 is formed into a substantiallyrectangular shape in which a pair of corners is partially rounded. Thewall portion 712 is formed in a top surface of the top plate 711.

The wall portion 712 includes a peripheral wall 713 and an inner wall714.

While a portion corresponding to one side of the top plate 711 is openedin the peripheral wall 713, the peripheral wall 713 is verticallyprovided from the top plate 711 along other sides of the top plate 711.The three inner walls 714 are disposed inside the peripheral wall 713.The inner walls 714 are vertically provided from the top plate 711 inparallel to one another, and the inner walls 714 extend inward whilebeing connected to the peripheral wall 713. End surfaces in the Z-axisdirection of the peripheral wall 713 and the inner walls 714 are flushwith one another. In the three inner walls 714, an inner wall 714 adisposed in the center is formed longer than two inner walls 714 b inthe X-axis direction. A leading end portion of the central inner wall714 a is a positioning unit 715 that the engaging units 121 and 131 ofthe lower insulating members 120 and 130 engage.

The wall 720 extends in the Z-axis direction, the top plate 711 isjoined to one end portion of the wall 720, and the bottom plate 730 isjoined to the other end portion. In a central portion in a Y-axisdirection of the wall 720, an opening 740 is formed to open the wall720. The opening 740 is formed along the Z-axis direction so as to openthe wall 720 from the top plate 711 to the bottom plate 730.

In the wall 720, portions that face each other with respect to theopening 740 are referred to as a first wall 720 a and a second wall 720b. The first wall 720 a and the second wall 720 b are formed into auniform shape from one end to the other end in the Z-axis direction. Asto sectional shapes of the first wall 720 a and second wall 720 b, aninner surface becomes a smooth concave surface as a whole as illustratedin FIG. 7. On the other hand, an outer surface of the first wall 720 aand second wall 720 b becomes a smooth convex surface as a whole so asto correspond to the inner surface shape of the main body 111 of thecontainer 100.

Similarly to the top plate 711, when viewed from above, the bottom plate730 is formed into a substantially rectangular shape in which the corneris partially rounded. The wall 720 is joined to the top surface of thebottom plate 730.

A state in which the side spacer 700 is assembled in the electrode body400 will be described below with reference to FIGS. 7 and 9.

FIG. 9 is a perspective view illustrating an assembly state of the sidespacer 700 and the electrode body 400 of the embodiment.

As illustrated in FIG. 9, the side spacers 700 are separately attachedto the curved portions 431 and 432 of the electrode body 400.Specifically, the side spacer 700 is attached to the electrode body 400such that one end portion to the other end portion in the winding axisdirection of each of the curved portions 431 and 432 is accommodated inthe opening 740.

In FIG. 7, the external form of the curved portion 432 is indicated byan alternate long and two short dashes line. Because the curved portions431 and 432 have the substantially identical external form, a positionalrelationship between the side spacer 700 and the curved portion 432 isdescribed by way of example, and the description of a positionalrelationship between the side spacer 700 and the curved portion 431 isomitted. As illustrated in FIG. 7, the side spacer 700 is attached tothe electrode body 400 such that the outer surface of the wall 720 isflush with a part of the surface of the curved portion 432. At thispoint, a part of the surface of the curved portion 432 is an areaincluding the top of the curved portion 432. Therefore, the curvedportion 432 is accommodated in the opening 740 of the side spacer 700.Because the inner surface of the wall 720 becomes the concave surface,the inner surface of the wall 720 abuts on the surface of the curvedportion 432 to stabilize the form of the curved portion 432 withoutdestroying the curved surface shape of the curved portion 432.

As illustrated in FIG. 9, the side spacer 700 is fixed to the bodyportion 430 of the electrode body 400 by an adhesive tape 380.Specifically, in the side spacer 700, two points separated by apredetermined gap from each other in the Z-axis direction are fixed tothe body portion 430 by the adhesive tape 380.

When the side spacer 700 is fixed to the body portion 430 of theelectrode body 400, the side spacer 700 extends from one end portion tothe other end portion of the body portion 430 in the winding axisdirection as illustrated in FIG. 9. At this point, the bottom plate 730of the side spacer 700 covers the other end portion of the body portion430. The base 710 that is of one end portion of the side spacer 700separates from one end of the body portion 430 by a predetermined gap S1in the winding axis direction.

A connection state of the side spacer 700 and the lower insulatingmembers 120 and 130 will be described below with reference to FIG. 8.

The connection state of the side spacer 700 and the lower insulatingmember 120 is identical to the connection state of the side spacer 700and the lower insulating member 130. Therefore, the connection state ofthe lower insulating member 130 and the side spacer 700 are described byway of example, and the description of the connection state of the lowerinsulating member 120 and the side spacer 700 is omitted.

As illustrated in FIG. 8, the engaging unit 131 projects from one end onthe outside of the lower insulating member 130. Ribs 133 extendingacross a total length of the engaging unit 131 are provided at both sideportions of the engaging unit 131. The ribs 133 enhance strength of thewhole engaging unit 131. A recess 131 a that is recessed along theX-axis direction is provided in the center at the leading end of theengaging unit 131. The recess 131 a engages the positioning unit 715 onthe top plate 711 of the side spacer 700. Specifically, the recess 131 ais pierced in the Z-axis direction, and opened on the positive side inthe X-axis direction, so that the recess 131 a can engage thepositioning unit 715 from the Z-axis direction and the X-axis direction.When the recess 131 a engaging the positioning unit 715, movement in thedirection intersecting the Z-axis direction of the recess 131 a, morespecifically, the movement in the Y-axis direction of the recess 131 ais restricted by the positioning unit 715. That is, because the movementin the Y-axis direction of the whole lower insulating member 130 isrestricted, the movement in the Y-axis direction of the cover platestructure 180 including the lower insulating member 130 is alsorestricted to position the cover plate structure 180

FIG. 10 is a side view illustrating a positional relationship betweenthe cover plate structure 180 and the side spacer 700 of the embodiment.

As illustrated in FIG. 10, the base 710 that is of one end portion ofthe side spacer 700 abuts on the cover plate 110 that is of a part ofthe over plate structure 180. Specifically, one end surface of the wallportion 712 of the base 710 abuts on the cover plate 110. Even in thisstate, as described above, the base 710 separates from one end of thebody portion 430 of the electrode body 400 by the predetermined gap S1in the winding axis direction (see FIG. 6). Therefore, even if the coverplate structure 180 is pressed from above, the force pressing the coverplate structure 180 is prevented from acting on one end portion of thebody portion 430.

A configuration example of the connection portion of the currentcollector and the tab with the leading plate interposed therebetweenwill be described below with reference to FIG. 11.

FIG. 11 is a sectional schematic diagram illustrating the cover platestructure 180 of the embodiment and a surrounding structure thereof.FIG. 11 illustrates a partial section of the energy storage device 10when the energy storage device 10 is cut by a YZ-plane passing through aline XI-XI in FIG. 3, and the side spacer 700 (see FIG. 2) on thepositive side in the X-axis direction is omitted in FIG. 11. Theelectrode body 400 is simplified and illustrated.

As illustrated in FIG. 11, the tab 420 of the electrode body 400 and thenegative electrode current collector 150 are electrically connected toeach other through the negative electrode leading plate 155 having aU-shape in section. For example, the connection structure in FIG. 11 isprepared by the following procedure.

For example, an end portion (first end portion) of the plate-likenegative electrode leading plate 155 and the tab 420 of the electrodebody 400 are joined to each other by ultrasonic welding. For example, anend portion (second end portion) on an opposite side to the first endportion of the negative electrode leading plate 155 is joined to thenegative electrode current collector 150 assembled in the cover platestructure 180 by laser welding. Then the negative electrode leadingplate 155 is deformed into a U-shape at a predetermined position betweenthe first end portion and the second end portion. Resultantly, theconnection structure between the tab 420 of the electrode body 400 andthe negative electrode current collector 150 through the negativeelectrode leading plate 155 having a U-shape in section is formed asillustrated in FIG. 11.

The upper spacer 500 is disposed between the end portion on the side, onwhich the tab 420 is provided, of the body portion 430 and the coverplate 110. More particularly, the joined portion of the tab 420 and thenegative electrode leading plate 155 is partitioned from the bodyportion 430 of the electrode body 400 by the upper spacer 500. The tab420 is disposed while inserted in the insertion portion 520 provided inthe upper spacer 500. The cushion sheet 600 is sandwiched between theupper spacer 500 and the body portion 430 of the electrode body 400.

The structure around the negative electrode leading plate 155 isillustrated and described in FIG. 11, and the structure around thepositive electrode leading plate 145 is also similar. That is, the tab410 of the electrode body 400 and the positive electrode currentcollector 140 are electrically connected to each other through thepositive electrode leading plate 145 (for example, see FIG. 2) having aU-shape section. The joined portion of the tab 410 and the positiveelectrode leading plate 145 is partitioned from the body portion 430 ofthe electrode body 400 by the upper spacer 500, and the tab 410 isdisposed while inserted in the insertion portion 520 provided in theupper spacer 500.

The electrode body 400 and the positive electrode current collector 140are connected to each other through the positive electrode leading plate145, and the electrode body 400 and the negative electrode currentcollector 150 are connected to each other through the negative electrodeleading plate 155, which allows the lengths (the lengths in the windingaxis direction (Z-axis direction)) of the tabs 410 and 420 of theelectrode body 400 to be relatively shortened.

That is, the widths (the lengths in the winding axis direction (Z-axisdirection)) of the electrode plates necessary for the production of theelectrode body 400 can relatively be shortened in the positive electrode450 and the negative electrode 460. This has an advantage from theviewpoint of production efficiency of the electrode body 400.

As illustrated in FIG. 11, a binding sheet 360 is disposed between thebody portion 430 of the electrode body 400 and the insulating sheet 350.

FIG. 12 is a perspective view illustrating a binding state of thebinding sheet 360 to the electrode body 400 of the embodiment.

As illustrated in FIG. 12, the binding sheet 360 is wound around thebody portion 430 of the electrode body 400. Specifically, the bindingsheet 360 is a belt-like member stabilizing the form of the body portion430, and the binding sheet 360 is wound around the outer periphery ofthe body portion 430. In the binding sheet 360, one end portion isplaced on the other end portion, and the end portions of the bindingsheet 360 are fixed to each other by an adhesive tape 390. In additionto the adhesive tape 390, the end portions of the binding sheet 360 maybe fixed to each other by an adhesive agent or thermal welding.Alternatively, a cyclic binding member may be used. The binding sheet360 is made of an insulating material having an electrolytesolution-resistant property. Specifically, PC, PP, PE, or PPS can becited as an example of the insulating material. The process of windingthe binding sheet 360 around the body portion 430 may be eliminated whenthe form of the body portion 430 is stabilized.

In the adhesive tapes 370, 380 and 390, the substrate is made of aninsulating material having an electrolyte solution-resistant property.Specifically, PC, PP, PE, or PPS can be cited as an example of theinsulating material. The adhesive layer provided on one surface of thesubstrate of each of the adhesive tapes 370 and 380 is also formed by anadhesive agent having the electrolyte solution-resistant property andthe insulating property.

A method for producing the energy storage device 10 will be describedbelow.

The tab 410 of the electrode body 400 is welded to a flat plateconstituting the positive electrode leading plate 145, and the tab 420of the electrode body 400 is welded to a flat plate constituting thenegative electrode leading plate 155. After the cover plate structure180 is assembled, the flat plate constituting the positive electrodeleading plate 145 is welded to the positive electrode current collector140 of the cover plate structure 180, and the flat plate constitutingthe negative electrode leading plate 155 is welded to the negativeelectrode current collector 150. After the welding, the flat plateconstituting the positive electrode leading plate 145 and the flat plateconstituting the negative electrode leading plate 155 are bent to formthe positive electrode leading plate 145 and the negative electrodeleading plate 155, respectively.

Then the side spacer 700 is attached to the body portion 430 of theelectrode body 400. Specifically, as illustrated in FIG. 7, the sidespacer 700 is separately attached in each of the curved portion 431 and432 of the body portion 430. On the side of the curved portion 431, theside spacer 700 is fixed to the body portion 430 by the adhesive tape380 after the positioning unit 715 of the side spacer 700 is engagedwith the engaging unit 121 of the lower insulating member 120 that is ofa part of the cover plate structure 180. On the side of the curvedportion 432, the side spacer 700 is fixed by the adhesive tape 380 tothe body portion 430 by the similar process. After the fixing, the coverplate 110 that is of a part of the over plate structure 180 abuts on thebase 710 that is of one end portion of the side spacer 700 asillustrated in FIG. 10.

Then, as illustrated in FIG. 12, the binding sheet 360 is wound aroundthe body portion 430 of the electrode body 400, and the end portions ofthe binding sheet 360 are fixed to each other by the adhesive tape 390.

FIG. 13 is a perspective view illustrating one process of a method forproducing the energy storage device 10 of the embodiment.

As illustrated in FIG. 13, the electrode body 400 around which thebinding sheet 360 is wound is accommodated in the main body 111 of thecontainer 100 in such a state.

Because the base 710 of the side spacer 700 abuts on the cover plate 110of the cover plate structure 180 as illustrated in FIG. 10, the sidespacer 700 and the electrode body 400 move toward the inside of the mainbody 111 of the container 100 by pushing the cover plate structure 180.Because the side spacer 700 slides along the inner peripheral surface ofthe main body 111 during the movement, the electrode body 400 issmoothly guided to the inside of the main body 111.

FIG. 14 is a sectional view illustrating a positional relationship amongthe side spacer 700, the electrode body 400, and the container 100 ofthe embodiment. In FIG. 14, the external form of the curved portion 432of the body portion 430 of the electrode body 400 is indicated by analternate long and two short dashes line.

As illustrated in FIG. 14, the side spacer 700 is disposed along theside surface constituting a short side of the accommodation recess 112when viewed from the winding axis direction. The inner surface shape ofthe corner of the accommodation recess 112 is rounded. Because the outersurface of the wall 720 of the side spacer 700 constitutes the smoothconvex surface so as to correspond to the rounded shape, the side spacer700 comes close contact with the main body 111 to stably hold theelectrode body 400. The curved portion 432 of the electrode body 400 isdisposed in the opening 740 of the side spacer 700 such that a part ofthe surface of the curved portion 432 is flush with the outer surface ofthe wall 720. Therefore, the body portion 430 of the electrode body 400can densely be accommodated in the main body 111 while the side spacer700 is used. When the electrode body 400 and the like are accommodatedin the main body 111 of the container 100, one end portion of the bodyportion 430 of the electrode body 400 faces the cover plate structure180.

Then the cover plate 110 is welded to the main body 111 to assemble thecontainer 100.

After the electrolyte solution is poured from the electrolyte solutionfilling port 117, the electrolyte solution filling plug 118 is welded tothe cover plate 110 to close the electrolyte solution filling port 117,thereby producing the energy storage device 10.

As described above, in the embodiment, because the cover plate structure180 abuts partially on one end portion of the side spacer 700 attachedto the electrode body 400, the electrode body 400 enters the container100 together with the side spacer 700 when the cover plate structure 180is pressed in assembling the electrode body 400 in the container 100.Accordingly, even if the electrode body 400 is not directly pressed, theelectrode body 400 can be accommodated in the container 100, and thedamage of the electrode body 400 can be prevented during the production.

The side spacer 700 extends from one end portion of the electrode body400 to the other end portion, so that the side spacer 700 can be slid tothe end with respect to the container 100 when the electrode body 400 isaccommodated in the container 100. Accordingly, the electrode body 400can easily be guided to the container 100.

The bottom plate 730 partially covering the other end portion of theelectrode body 400 is provided in the other end portion of the sidespacer 700, so that the other end portion of the electrode body 400 canbe prevented from contacting partially with the container 100 after theelectrode body 400 is accommodated in the container 100. Therefore, thedamage of the electrode body 400 can further be prevented.

The top plate 711 partially covering one end portion of the electrodebody 400 is provided in the side spacer 700, so that one end portion ofthe electrode body 400 can be prevented from contacting with thecontainer 100 after the electrode body 400 is accommodated in thecontainer 100. Therefore, the damage of the electrode body 400 canfurther be prevented.

The engaging unit 131 of the cover plate structure 180 engages thepositioning unit 715 of the side spacer 700 to position the cover platestructure 180 with respect to the side spacer 700. Accordingly, theelectrode body 400 can be accommodated in the container 100 while thepositional relationship between the side spacer 700 and the cover platestructure 180 is stabilized.

The lower insulating member 130 is provided between the cover plate 110and the electrode body 400, so that the insulating property between thecover plate 110 and the electrode body 400 can be maintained by thelower insulating member 130. The engaging unit 131 is provided in thelower insulating member 130, so that the position of the lowerinsulating member 130 can be stabilized.

Because one end portion of the side spacer 700 separates from theelectrode body 400 in the winding axis direction, the side spacer 700does not interfere with one end portion of the electrode body 400 evenif the cover plate structure 180 is pushed. Therefore, the damage of theelectrode body 400 can further be prevented during the production.

Even if the tabs 410 and 420 are provided in the electrode body 400, thedamage of the tabs 410 and 420 can be prevented because the electrodebody 400 can be accommodated in the container 100 without directlypressing the electrode body 400.

Because the portion abutting on the side spacer 700 of the cover platestructure 180 is the cover plate 110, the portion can be formed moreeasily than the case that another portion abuts on the side spacer 700.

Other Embodiments

The energy storage device of the invention is described above based onthe embodiment. However, the present invention is not limited to theembodiment. Various modifications of the embodiment that are made bythose skilled in the art or various configurations constructed by acombination of the plural components are also included in the presentinvention as long as the modifications and the configurations do notdepart from the scope of the present invention.

For example, the number of electrode bodies 400 included in the energystorage device 10 is not limited to one, but at least two electrodebodies 400 may be provided. In the case that the energy storage device10 includes the plural electrode bodies 400, a dead space can be reducedin a corner of the container 100 compared with the case that the singleelectrode body 400 is accommodated in the container 100 having theidentical volume (capacity). A ratio of the electrode body 400 to thecapacity of the container 100 can be increased, and therefore thecapacity of the energy storage device 10 can be increased.

There is no particular limitation to a positional relationship betweenthe positive electrode-side tab 410 and the negative electrode-side tab420 in the electrode body 400. For example, in the winding typeelectrode body 400, the tabs 410 and 420 may be disposed on the oppositeside to each other in the winding axis direction. In the case that theenergy storage device 10 includes the laminated type electrode body, thepositive electrode-side tab and the negative electrode-side tab may beprovided while projecting in different directions, when the positiveelectrode-side tab and the negative electrode-side tab are viewed fromthe laminated direction.

The electrode body 400 included in the energy storage device 10 is notalways formed into the winding type. For example, the energy storagedevice 10 may include a stacked type electrode body in which plate-likeelectrode plates are stacked. For example, the energy storage device 10may include an electrode body having a bellows-shaped stacked structureformed by repeating a mountain fold and a valley fold of an elongatedbelt-like electrode plate.

The side spacer 700 may be formed into any shape as long as the curvedportions 431 and 432 can be exposed from one end to the other end of theelectrode body 400 in the winding axis direction. In the embodiment, byway of example, the integral side spacers 700 are separately provided inthe curved portions 431 and 432 of the electrode body 400.Alternatively, the side spacer may be divided.

FIG. 15 is a perspective view illustrating a state in which a sidespacer according to a modification of the embodiment is attached to theelectrode body 400. In the following description, sometimes the samecomponent as the above embodiment is designated by the same referencesign to omit the description thereof.

As illustrated in FIG. 15, a side spacer 700A is one in which the sidespacer 700 of the embodiment is divided with respect to the substantialcenter in the Z-axis direction, and the side spacer 700A includes afirst member 760 and a second member 770. The first member 760 includesthe base 710 and a wall 721. The second member 770 includes the bottomplate 730 and a wall 722. There is a predetermined space between thewall of the first member 760 and the wall 722 of the second member 770in the Z-axis direction. A slit between the first wall 721 a and thesecond wall 721 b in the wall 721 and a slit between the first wall 722a and the second wall 722 b in the wall 722 constitute an opening 740 a.The surfaces of the curved portions 431 and 432 are partially exposedfrom one end to the other end of the electrode body 400 in the windingaxis direction by the opening 740 a.

In the embodiment, by way of example, the side spacers 700 areseparately provided in the curved portions 431 and 432 of the electrodebody 400. Alternatively, the plural side spacers may integrally beprovided.

FIG. 16 is a perspective view illustrating a state in which a sidespacer according to another modification of the embodiment is attachedto the electrode body 400.

As illustrated in FIG. 16, side spacers 700B attached to each of thecurved portion 431 and 432 are integrally joined to each other by a beam780. Specifically, the beam 780 extending in the X-axis direction isbridged in one end portion of each of the side spacers 700B. The beam780 may be placed on any point as long as a capacity of the electrodebody 400 is not largely decreased. Thus, because the pair of sidespacers 700B is integrally formed by the beam 780, rigidity can beenhanced, and the assembly can easily be performed.

In the embodiment, the outer surface of the wall 720 of the side spacer700 is the smooth convex surface by way of example. Alternatively, theouter surface of the wall 720 may be formed into any shape as long asthe outer surface corresponds to the inner surface shape of the mainbody 111 of the container 100.

FIG. 17 is a sectional view illustrating a positional relationshipbetween a side spacer according to still another modification of theembodiment and the container 100.

As illustrated in FIG. 17, a main body 111 c of a container 100C isformed into an inner surface shape having a substantially right anglecorner. An outer surface of the wall 720 c of the side spacer 700C isformed into a shape having the substantially right angle cornercorresponding to the inner surface shape of the main body 111 c. Even inthis case, the side spacer 700C is comes into close contact with themain body 111 c, so that the electrode body 400 can stably be held.

In the embodiment, by way of example, the cover plate 110 abuts on thebase 710 that is of one end portion of the side spacer 700.Alternatively, a target abutting on the base 710 may be a portion otherthan the cover plate 110 as long as the portion is included in the coverplate structure 180, and the target may be a member (such as the lowerinsulating members 120 and 130, the positive electrode current collector140, and the negative electrode current collector 150) that is locatedinside the container 100 with respect to the cover plate 110.

In the embodiment, by way of example, the positioning unit 715 of theside spacer 700 is the leading end portion of the inner wall 714 a, andthe engaging unit 131 of the cover plate structure 180 includes therecess 131 a engaging the positioning unit 715. However, the positioningunit 715 and the engaging unit 131 may be formed into any shape as longas the positioning unit 715 and the engaging unit 131 can be engaged andpositioned. For example, the positioning unit 715 is formed into a bossprojecting in a Z-axis direction, and a hole into which the boss isinserted may be provided in the engaging unit 131. In this case, themovement in the X-axis direction can be controlled in addition to theY-axis direction.

In the embodiment, by way of an example, the energy storage device 10includes the insulating sheet 350 and the binding sheet 360. However, itis not always necessary to provide the insulating sheet 350 and thebinding sheet 360.

It is noted that a configuration constructed by any combination of theembodiment and the modifications is also included in the presentinvention.

INDUSTRIAL APPLICABILITY

The present invention can be applied to energy storage devices such as alithium ion secondary battery.

DESCRIPTION OF REFERENCE SIGNS

10 energy storage device

100, 100C container

110 cover plate

110 a through-hole

110 b through-hole

111, 111 c main body

112 accommodation recess

113 bottom

117 electrolyte solution filling port

118 electrolyte solution filling plug

120, 130 lower insulating member

120 a, 130 a through-hole

120 b, 130 b engagement projection

121,131 engaging unit

122,132 attaching unit

125,135 upper insulating member

125 a, 126, 135 a, 140 a, 150 a through-hole

131 a notch

133 rib

140 positive electrode current collector

145 positive electrode leading plate

150 negative electrode current collector

155 negative electrode leading plate

160 swelling unit

170 safety valve

180 cover plate structure

200 positive electrode terminal

210, 310 fastening unit

300 negative electrode terminal

350 insulating sheet

360 binding sheet

370, 380, 390 adhesive tape

400 electrode body

410 ,420 tab

411, 421 projection

430 body portion

431, 432 curved portion

450 positive electrode

460 negative electrode

470 a, 470 b separator

470 c, 470 d stick-out portion

500 upper spacer

510 latch

520 insertion portion

600 cushion sheet

700, 700A, 700B, 700C side spacer (spacer)

710 base

711 top plate

712 wall portion

713 peripheral wall

714, 714 a, 714 b inner wall

715 positioning unit

720, 720 c, 721, 722 wall

720 a, 721 a, 722 a first wall

720 b, 721 b, 722 b second wall

730 bottom plate

740, 740 a opening

760 first member

770 second member

780 beam

1. An energy storage device, comprising: an electrode body in which anelectrode is stacked; a container in which the electrode body isaccommodated; a cover plate structure including a cover plate thatcloses the container; and a spacer that is attached to the electrodebody, wherein the spacer includes a positioning unit that positions thecover plate structure, and wherein an engaging unit, engaging with thepositioning unit, is provided in the cover plate structure.
 2. Theenergy storage device according to claim 1, wherein the cover platestructure includes a lower insulating member, and wherein the lowerinsulating member includes the engaging unit.
 3. The energy storagedevice according to claim 2, wherein the lower insulating member isprovided between the cover plate and the electrode body.
 4. The energystorage device according to claim 2, wherein the positioning unitprojects from a wall portion of the spacer toward the electrode body onan outer surface of the lower insulating member opposite to the coverplate.
 5. The energy storage device according to claim 2, wherein theengaging unit projects from one end of the lower insulating plate towardthe spacer.
 6. An energy storage device, comprising: an electrode bodyin which an electrode is stacked; a container in which the electrodebody is accommodated; a cover plate structure including a cover platethat closes the container; and a spacer that is attached to theelectrode body, wherein the spacer includes a positioning unit thatpositions the cover plate structure, wherein an engaging unit, engagingwith the positioning unit, is provided in the cover plate structure, andwherein the engaging unit includes a recess that is recessed along afirst direction which is a long-side direction of the cover plate. 7.The energy storage device according to claim 6, wherein the engagingunit projects from one end of a lower insulating plate provided betweenthe cover plate and the electrode body toward the spacer, wherein theengaging unit includes ribs extending from the one end of the lowerinsulating plate, and wherein the recess is formed so as to besandwiched between the ribs.
 8. An energy storage device, comprising: anelectrode body in which an electrode is stacked; a container in whichthe electrode body is accommodated; a cover plate structure including acover plate that closes the container; and a spacer that is attached tothe electrode body, wherein the spacer includes a positioning unit thatpositions the cover plate structure, wherein an engaging unit, engagingwith the positioning unit, is provided in the cover plate structure, andwherein the positioning unit and the engaging unit are provided indifferent members and engage in a first direction which is a long-sidedirection of the cover plate.